1. Field of the Invention
The present invention relates to a supersonic pulverizing device.
2. Description of the Prior Art
Nano powders have special optics, heat, magnetism and mechanics characters, so they are widely used to nano-coating, nano inkjet colors, bathroom equipment, photo catalyst, functional fiber textile products and edible products and the like. They have expected effects. For example, nano powders are used to bathroom equipment to get an anti-pollution effect. Nano powders are gradually popular. So far, there is a ball grinding method to produce nano powders. As shown in FIG. 1, a ball grinding machine 300 comprises a pair of rollers 301 which are turned in the same direction. A grinding cylinder 302 made of steel is disposed on the rollers 301. A plurality of grinding balls 303 (steel balls or porcelain balls) and a source material 200 are placed in the grinding cylinder 302. The rollers 301 are activated to bring the grinding cylinder 302 to turn. The grinding balls 303 and the source material 200 are attached to the inner wall of the grinding cylinder 302 due to centrifugal force and risen up along with the turning of the grinding cylinder 302. When the grinding balls 303 and the source material 200 are risen to a certain height where the gravity is larger than the centrifugal force, the grinding balls 303 and the source material 200 will free fall to transform the potential energy into kinetic energy, such that the grinding balls 300 strikes against the source material 200 and the source material 200 is crashed into powder.
However, it is not easy to control the rotational speed of the ball grinding machine 300. When the rotational speed is too high, the grinding balls 303 will tightly attach to the inner wall of the grinding cylinder 302 and won't free fall to strike against the source material 200. When the rotational speed is too low, the grinding balls 303 are unable to rise up along with the turning of the grinding cylinder 302 to get enough potential energy. In consideration of this, an air flow pulverizing technique is developed. Referring to FIG. 2, an air flow pulverizing machine 400 has a main body 401. The main body 401 has a pulverizing room 402, a plurality of air flow nozzles 403 around the pulverizing room 402, and a feeding nozzle 404. The source material 200 is sent to the pulverizing room 402 from the feeding nozzle 404, and the compressed air enters the pulverizing room 402 from the air flow nozzles 403 at a supersonic speed. The source material 200 will be crushed into powders by the injected air flow. However, the source material 200 is crushed in the pulverizing room 402 at a supersonic speed, the inner walls of the feeding nozzle 404 and the pulverizing room 402 are easily be worn by the source material 200. The air flow pulverizing machine 400 needs a cooling device to cool the heat generated by friction. Particularly, constant friction wore out the inner wall of the pulverizing room 402, and the source material 200 may be polluted by the material of the main body 401. Accordingly, the inventor of the present invention has devoted himself based on his many years of practical experiences to solve this problem.